The Role of Vegetation in Elevational Diversity Patterns of Tenebrionid Beetles in Central Italy

Abstract

Vegetation tends to vary in a systematic fashion along elevational gradients, leading to the possibility of recognizing distinct vegetational belts, which are frequently used to describe and interpret elevational variations in biodiversity. However, anthropogenic changes can create landscapes dominated by secondary grasslands in areas formerly occupied by forests, thus altering the natural sequence of vegetation types. The present research illustrates how the distribution of tenebrionid beetles in central Italy is influenced by secondary vegetation. Classical schemes of vegetational belts were modified into a scheme of main vegetation types that include secondary vegetations. Tenebrionid species presence/absence in each vegetation type was then assessed. Species richness tended to decrease with elevation in both natural and secondary vegetations. Geophilous (ground-dwelling) species (which include many endemics) prevailed in natural and secondary grasslands, while xylophilous species (associated with trees) prevailed in the natural forests. Similarities in tenebrionid composition indicated the presence of two main groups: one associated with forests and the other with natural and secondary grasslands. Geophilous species prevailed among tenebrionids with Mediterranean distributions, whereas xylophilous species prevailed among species distributed mainly in Europe and the Palearctic. High values of richness, biogeographical complexity and proportion of endemics make secondary vegetations of high conservation concern.